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Abstract:

In a method for the treatment of a substrate surface of a flat substrate
with a process medium at the substrate underside, the process medium has
a removing or etching effect on the substrate surface. The substrates are
wetted with the process medium from below in a manner lying horizontally.
The upwardly facing substrate top side is wetted or covered with water or
a corresponding protective liquid over a large area or over the whole
area as protection against the process medium acting on the substrate top
side.

Claims:

1. A method for treating a substrate surface of a flat substrate with a
process medium at the substrate underside, wherein the process medium has
a removing or etching effect on the substrate surface, the method
comprising the steps of: wetting the substrates with the process medium
from below with the substrates lying horizontally; and wetting or
covering the upwardly facing substrate top side with water or a
corresponding protective liquid over a large area or over the whole area
as protection against the process medium or the outgassings thereof
acting on or reaching the substrate top side.

2. The method according to claim 1, comprising applying the protective
liquid to the substrate top side before the substrate or the substrate
underside is wetted with the process medium.

3. The method according to claim 1, wherein the protective liquid is
applied to moving substrates or substrate top sides in a continuous
method by stationary application devices or spray nozzles or surge pipes.

4. The method according to claim 1, wherein the protective liquid is
applied multiple times with time intervals inbetween to the substrate top
side.

5. The method according to claim 1, wherein the protective liquid is
applied to the substrate top side one single time before the substrate is
situated above a tank containing the process medium therein.

6. The method according to claim 1, wherein the protective liquid is
applied to the substrate top side controlled in such a manner that it is
applied exclusively to the substrate top side by starting of the
application only when a substrate is situated under an application
device, and by stopping application of the protective liquid when the
substrate is still situated under the application device.

7. The method according to claim 1, wherein the protective liquid is
applied to the substrate top side with a two-dimensionally distributed
profile by spray nozzles designed for producing a two-dimensionally
distributed spray mist.

8. The method according to claim 1, wherein the protective liquid is
applied to the substrate top side in a punctiform fashion in order to
cover the substrate surface over a large area or over the whole area.

9. The method according to claim 1, wherein when the substrate underside
is wetted with the process medium, an exothermic reaction takes place
with a temperature increase of at least 10.degree. C., and the protective
liquid is applied to the substrate top side in a layer having a thickness
of approximately 1 mm or greater.

10. The method according to claim 1, wherein when the substrate underside
is wetted with the process medium, no significant temperature increase
takes place and the protective liquid is applied to the substrate top
side in a layer having a thickness of approximately 50 μm to 200
μm.

11. The method according to claim 1, wherein the substrate underside is
wetted with the process medium by touching a liquid level of the process
medium in a tank without deeper immersion of the substrates.

12. The method according to claim 1, wherein the substrates are rinsed
after the treatment with the process medium, wherein the protective
liquid is also rinsed or removed from the substrate top side.

13. The method according to claim 1, wherein the protective liquid has a
higher viscosity than water.

14. The method according to claim 1, wherein the substrates which are
treated are pierced or have perforations, and wherein the protective
liquid has a higher viscosity than water.

15. The method according to claim 1, wherein several application devices
are arranged one next to the other in a direction approximately
transverse to a continuous-passage path of the substrates, and the
substrates are brought in rows one after the other onto the
continuous-passage path such that each substrate passes beneath one of
the application devices.

16. A device for carrying out the method according to claim 1, wherein at
least one application device is provided for applying water or protective
liquid to the upwardly facing substrate top side above a
continuous-passage path for transporting the substrates over a tank
containing the process medium therein.

17. The device according to claim 16, wherein the at least one
application device is arranged upstream of the tank with the process
medium therein.

18. The device according to claim 16, wherein at least one said
application device is arranged above the tank with the process medium
therein.

19. The device according to claim 16, wherein a row of application
devices is provided transverse to the continuous-passage path of the
substrates, with application devices being distanced one from each other,
by at least one width of a substrate.

20. The device according to claim 16, wherein, substrate sensors are
provided upstream of the application devices along the continuous-passage
path of the substrates for detection of a substrate being moved along the
continuous-passage path.

21. The method according to claim 13, wherein the protective liquid is
PEG or phosphoric acid.

22. The device according to claim 18, wherein a further application
device is arranged upstream of the tank.

23. The device according to claim 16, wherein the at least one
application device is connected to a supply tank situated higher than the
at least one application device.

Description:

FIELD OF APPLICATION AND PRIOR ART

[0001] The invention relates to a method for treating a substrate surface
in accordance with the preamble of claim 1, and to a device suitable for
carrying out the method.

[0002] DE 10 2005 062 527 A1 and DE 10 2005 062 528 A1 disclose methods
for treating planar substrates on one side, to be precise for treating
the substrate undersides or the downwardly facing substrate sides. When
this method is applied, it is possible here despite extraction by suction
below the substrates, for the substrate top side to be slightly attacked
by reaction gases or outgassings from the process medium, under certain
circumstances also through direct contact. Moreover, depending on the
transport speed of the substrates, the mixture of the process medium or
the chemical and the state of the substrate surfaces, an undesired edge
wraparound of the process medium can occur. As a result, the substrate
top side can be attacked and also be impaired optically or, which is even
worse, functionally.

OBJECT AND HOW IT IS ACHIEVED

[0003] The invention is based on the object of providing a method
mentioned in the introduction and a corresponding device with which
problems in the prior art can be eliminated and, in particular, a
possibility is provided for preventing an upwardly facing substrate top
side of the substrate from being exposed to the undesirable and harmful
effect of the process medium, in particular in outgassed form.

[0004] This object is achieved by means of a method comprising the
features of Claim 1 and also a device comprising the features of Claim
16. Advantageous and preferred configurations of the invention are the
subject matter of the further claims and are explained in greater detail
below. Some of the features below are described only for the method or
only for the device. However, irrespective of this they are intended to
be applicable both to the method and to the device. The wording of the
claims is incorporated by express reference in the content of the
description.

[0005] It is provided that the substrate surface or the substrate
underside is treated with a usually liquid process medium. The process
medium has a removing or etching effect on the substrate surface, for
example for the polish-etching or edge insulation of a silicon substrate
for a solar cell. In this case, the substrates are wetted with the
process medium from below in a manner lying horizontally which can be
done in various ways known from the prior art. According to the
invention, the upwardly facing or directed substrate top side is wetted
or covered with water or some other corresponding protective liquid over
a large area or advantageously even over the whole area. This acts as
protection against the process medium or outgassings therefrom acting on
or reaching the substrate top side; it can therefore as it were, be kept
away therefrom. The water or the protective liquid therefore forms a
protective layer on the substrate top side, such that the latter cannot
be damaged by the process medium. The advantage of a liquid such as water
or some other protective liquid as a protective layer or protective
medium is that a liquid can easily be applied and can easily be removed
again and does not bring about any mechanical impairment of the substrate
top side, that is to say scratching or the like. Furthermore, the water
or generally the protective liquid can advantageously be chosen such that
no reaction whatsoever with the substrate top side takes place, nor any
other negative impairment. Finally, it is additionally possible for the
water or the protective liquid to be coordinated with the choice of
process medium in such a way that water or a corresponding protective
liquid running down from the substrate top side can pass into the process
medium and possibly indeed dilutes the latter. However, on account of the
small quantity, only an insignificant and otherwise no negative
impairment of the effect, generally of the etching effect, of the process
medium is brought about. Even further explanations in this respect will
be given below.

[0006] It is advantageously possible to apply the protective liquid to the
substrate top side before the substrate or the substrate underside is
wetted with the process medium. In particular, the application of the
protective liquid is even effected before the substrate is moved over a
tank with the process medium therein, that is to say temporally
distinctly before that or on a transport path approximately half a metre
or less upstream thereof. What can thereby be achieved is that protective
liquid running down cannot actually pass into the tank with the process
medium therein in the first place. For the customary time of a few
seconds or a few minutes for which the treatment with the process medium
above the tank lasts, a single application of protective liquid to the
substrate top side may suffice.

[0007] In a further configuration of the invention, the protective liquid
is applied to the moved substrates or the substrate top sides thereof in
a continuous method.

[0008] This can advantageously be effected by means of a stationary
application device in the form of spray nozzles or spray pipes, but
advantageously with little pressure, for example also by means of surge
pipes. A metering can easily be set for a desired quantity of liquid on
the substrate top side or thickness of a liquid film.

[0009] Even though it may suffice in many cases to apply the protective
liquid to the substrate top side only once, provision can advantageously
be made for applying the protective liquid multiply or at time intervals
to the substrate top side, or for renewing the protective film formed
thereby. This can also be effected, for example, by the protective liquid
being applied while the substrates run above the tank with the process
medium therein. In this case, either application can be effected very
precisely, such that as little protective liquid as possible passes into
the tank, or a specific delimited region can be provided or the
substrates are withdrawn again, although this is generally excessively
complicated.

[0010] As an alternative, the protective liquid can be applied to the
substrate top side only one single time, and this is in particular before
the substrate is situated above the tank with the process medium therein.
The protective liquid can be applied to the substrate top side in a
controlled manner such that it is present only on substrate top side.
This is possible by starting of the application only when a substrate is
situated under an application device. In similar manner it is stopped
when the substrate is still situated under the application device.
Preferably the position or adjustment of an adducted substrate is
detected by means of substrate sensors, and the application device is
controlled depending on this. Alternatively the position of the
substrates is calculated on the basis of their application, and this can
be passed on to a control device of the apparatus for the application
nozzles. This way it is possible for a layer of the protective liquid to
be formed, which will not drool down at the edge of the substrate, so
that these may be treated with the process medium.

[0011] With correspondingly designed application devices mentioned above,
in one configuration of the invention, the protective liquid can be
applied to the substrate top side with a two-dimensionally distributed
profile. For this purpose corresponding application devices can be
designed, for example as spray nozzles, such that they produce a
two-dimensionally distributed spray mist or, as surge pipes, a wide water
screen. This is suitable, firstly for covering the substrate top sides
with the protective liquid before movement over the tank with process
medium. Furthermore, easy application of protective liquid is made
possible if the latter has no negative interaction with the process
medium.

[0012] As an alternative to a two-dimensional distributed application of
the protective liquid to the substrate top side, this can be effected
with a two-dimensionally distributed profile or in punctiform. This
means, therefore, that from one or a few application devices, the
protective liquid is sprayed or dropped onto the substrate top side in
relatively punctiform fashion and then flows. The substrate surface can
thus ultimately be covered over a large area or over the whole area, in
which case, given known properties of the substrate top side, the
temperature and also the properties of the protective liquid, the
quantity thereof can be determined relatively precisely such that only a
small proportion overflows over the substrate and can pass downwards into
the process medium.

[0013] In the method it can be provided that when the substrate underside
is wetted or treated with the process medium, an exothermic reaction
takes place with a temperature increase of at least 10° C. A
relatively thick layer of protective liquid can then advantageously be
applied to the substrate top side, for example with a thickness of more
than 0.5 mm or more than 1 mm, up to 1.5 mm in the case of water and even
thicker in the case of protective liquids having a higher viscosity. As a
result, a large portion of the protective liquid can evaporate as a
result of the temperature increase and a sufficiently effective
protective layer can still remain.

[0014] Alternatively, a temperature increase during the treatment of the
substrate underside with the process medium can be omitted. A
significantly smaller layer thickness for the protective liquid on the
substrate top side then suffices, for example less than 0.2 mm or even
less than 0.05 mm, actually just a thin film. However, it can have an
abovementioned thickness in this case, too.

[0015] In a further configuration of the invention it can be provided that
during treatment the substrate underside touches a liquid level of
process medium in a tank, without the substrates being immersed more
deeply. They can then as it were float on the surface of the process
medium. In this case, without protective liquid, there may be the risk of
process medium adhering to the edges of the substrate and possibly even
reaching the substrate top side with corresponding negative consequences.
Alternatively, the substrate underside can be sprayed with the process
medium, although here the risk is even greater that the process medium
sprayed upwards will pass upwards past the outer edges of the substrates
and then settle on the substrate top sides at least in the edge regions.
In the case of such spraying of the substrate undersides with the process
medium from below, it is even less critical if an excessively applied
amount of protective liquid drips down from the substrate, since it is
then not necessarily mixed with the process medium that is sprayed
against the substrate underside. The protective liquid then possibly
passes into a common collecting tank, that it can possibly be separated
there or alternatively, by means of corresponding treatment here the
process medium can be present with the desired concentration.

[0016] After the treatment of the substrates with the process medium, said
substrates can be rinsed. In this case, it can be provided that the
protective liquid is also rinsed or removed from the substrate top side.

[0017] Furthermore, in this case, in accordance with a further aspect of
the invention such substrates which are pierced or have perforations can
also be protected, as it were, during an etching process on the substrate
underside, from the etching effect reaching the substrate top side.
Primarily a region around the perforations is thereby jeopardised.
Therefore, a substrate can be protected not only from an edge wraparound
of the process medium or settling from above, but also from the process
medium ascending through perforations, for example on account of
capillary action.

[0018] Alongside water or pure water, an appropriate protective liquid is
one having a higher viscosity. One example thereof is PEG having a
viscosity with a factor of 2 to more than 3 above that of water, or for
example also up to a factor of 3.8 in the case of phosphoric acid as
protective liquid. The phosphoric acid can also specifically prevent a
situation in which, on account of the concentration gradient, by way of
example, an etching solution comprising phosphoric acid and HF, in the
case of pierced substrates, is drawn upwards not only by the capillary
action but also on account of the concentration gradient, as would be
present in the case of water.

[0019] Other protective liquids can have an even much higher viscosity for
an even further improved protective effect or layer thickness. What is
achieved by means of the higher viscosity is that the protective liquid
is as it were somewhat less runny and does not run as easily from the
substrate top side.

[0020] Preferably several application devices are provided neighbouring
each other in a direction approximately transverse to a
continuous-passage path of the substrates. The substrates can preferably
be by laid onto the continuous-passage path in rows one after the other
and each of them pass exactly under one application device.

[0021] In the device according to the invention it is actually provided
that, above a continuous-passage path for the substrates, application
devices are provided, advantageously in the form of nozzles. They can be
arranged either exclusively upstream of the tank with the process medium
therein, above the tank or both upstream of the tank and above the tank.
The application devices are advantageously designed such that they can be
adapted to the size, number of substrates alongside one another and also
throughput speed such that protective liquid is applied to the substrate
top sides only to the desired extent and not to excess or only
insignificantly to excess.

[0022] Preferably at least one application device is arranged upstream of
the tank with the process medium therein, wherein especially preferably
one single row of application devices is provided transverse to the
continuous-passage path of the substrates. The application devices are
distanced one from the other, wherein in particular their distance is at
least one width of a substrate.

[0023] For providing the application devices with liquid the can be
connected to a supply tank, which is situated higher than the application
devices. In this way the afflux of protective liquid to the application
devices with continuous pressure can be reached by gravity alone.

[0024] In an embodiment of the invention substrate sensors are provided
upstream of the application devices, seen along the continuous-passage
path of the substrates, for detection of a substrate being moved closer
as well as for detection of a substrate moved in passing by. Preferably
these are optical sensors.

[0025] These and further features emerge not only from the claims but also
from the description and the drawings, wherein the individual features
can in each case be realised by themselves or as a plurality in the form
of subcombination in an embodiment of the invention and in other fields
and can constitute advantageous and inherently protectable embodiments
for which protection is claimed here. The subdivision of the application
into individual sections and sub-headings do not restrict the general
validity of the statements made thereunder.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Exemplary embodiments of the invention are schematically
illustrated in the drawings and are explained in greater detail below. In
the drawings:

[0027]FIG. 1 shows a lateral sectional illustration of an apparatus
according to the invention for the treatment of substrate undersides
while water as protective film is applied to the substrate top sides,

[0029]FIG. 3 shows a top view of an alternative apparatus according to
the invention with less application nozzles and with substrate-sensors
upstream.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0030]FIG. 1 illustrates, as a device according to the invention, an
apparatus 11 in lateral section comprising a tank 13, in which is
situated etching solution 15 as process medium. From the left, substrates
20 with their substrate underside 21 facing downwards and a substrate top
side 22 facing upwards are transported towards the right on a
continuous-passage path composed of transport rollers 24. They then pass
on the transport rollers 24 over the tank 13. As is known from DE 10 2005
062 527 A1 and DE 10 2005 062 528 A1 described in the introduction, in
accordance with a first possibility, by means of the transport rollers 24
which reach into the etching solution 15 with their lower region, said
etching solution 15 will be applied to the substrate undersides 21. Fresh
or conditioned etching solution 15 is introduced into the tank 13 via a
feed pipe 16. As an alternative or in addition to wetting of the
substrate undersides 21 by means of the transport rollers 24, a spray
pipe 17 can be provided, having an upwardly facing spray nozzle 18.
Etching solution 15 can thus be sprayed onto the substrate undersides 21.

[0031] Furthermore, additionally in accordance with DE 10 2005 062 527 A1,
means for suction extraction of gas that outgasses from the etching
solution 15 can be provided above the surface of the etching solution and
below the transport plane of the substrates.

[0032] Distinctly before the substrates 20 are introduced over the tank
13, they are sprayed with water by an application nozzle 26 arranged
above them, said water forming a protective film 29 on the substrate top
side 22. In this case, being sprayed with water 27 can advantageously be
effected two-dimensionally or the application nozzle 26 can extend over
the entire width of the substrate 20. Instead of the application nozzle,
the nozzles of which can be at a distance of a few cm from one another,
an abovementioned surge pipe with holes or slots can also be used. When
the substrate 20 passes below the application nozzle 26, the entire
substrate top side 22 is then sprayed or wetted with water 27 and a
whole-area protective film 29 is thus formed. The advantage of spraying,
particularly if it is effected over the whole area, in this case resides
in the fact that it is then ensured that the entire substrate top side 22
is covered by the protective film 29. If the water 27 is intended to
proceed merely from a single location, then it might happen that, by way
of example, contaminated regions or the like on the substrate top side 22
are not wetted or covered and consequently not protected. Advantageously,
three holes per substrate are provided on the application nozzle 26 or on
the surge pipe.

[0033] If the etching solution 15 is then applied to the substrate
underside 21 in a known manner above the tank 13, then the substrate top
sides 22 are still covered with the protective film 29 and thus protected
from the etching solution 15 having an effect. In order to prevent the
situation in which regions of the substrate top side 22 are exposed or a
protective film 29 is no longer present here, for example because the
water 27 has run away or partly evaporated as a result of the high
temperature during etching, water 27 can be applied again by means of a
further application nozzle 26'. Firstly, this additional application
nozzle 26' can be designed like the application nozzle 26 upstream of the
tank 13, that is to say can produce a rather two-dimensionally
distributed, relatively fine spray mist or cover an area region of the
substrate top side 22.

[0034] If the application nozzle 26' is arranged, however, such that,
during the etching method to be carried out, the protective film 29
possibly already becomes thin in places but is still present, then it
suffices for water to be resupplied in any form at all. It is thus
possible to prevent a situation in which the protective film 29 as it
were becomes too thin or is omitted in places. The advantage of such a
punctiform application of water 27 to the substrate top side 22 in
accordance with a second possibility is that it is not necessary to
effect spraying, because during such spraying some of the water 27
inevitably runs past the substrate 20 into the tank 13. Dripping down at
the outer edges of the substrate 20 cannot be prevented, however. Since
only a very small quantity can drip down or the dripping-down of only
very small quantities cannot be avoided, however, as a result hardly any
dilution of the etching solution 15 will take place and, consequently,
the etching effect will scarcely be impaired. Primarily if the etching
solution 15 is applied on to the spray pipe 17 together with spray nozzle
18, it can be supplied in such a way that it is not diluted by water 27.

[0035] The enlarged illustration in FIG. 2 firstly reveals how the etching
solution 15 is applied to the substrate underside 21 by means of the
left-hand transport roller in accordance with DE 10 2005 062 528 A1. As a
result, a kind of layer comprising etching solution 15 is formed on the
substrate underside 21, which brings about the etching process there. A
spray pipe 17 with a spray nozzle 18 is illustrated on the right, said
spray nozzle spraying etching solution 15 onto the substrate underside
21. In this case, the illustration shows on the right how some of the
sprayed etching solution 15 is sprayed past the substrate 20 and can
possibly fall onto a substrate top side 22 of an adjacent substrate
moving or arranged alongside on the right. However, the protective film
of water present on said substrate can prevent adverse impairment.

[0036] Furthermore, the illustration shows how some water 27 drips down
from the substrate 20 on the left and right thereof. This water 27 passes
into the etching solution in the tank 13 and dilutes said etching
solution somewhat. However, since the quantity of water may be very
small, particularly in relation to the quantity of etching solution, this
circumstance is virtually negligible or can be taken into account
accordingly when the mixture of the etching solution 15 is prepared.

[0037] Furthermore, it can be seen from FIG. 2 that even an application of
a relatively large amount of water 27 as a protective film 29 to the
substrate top side 22 need not necessarily be harmful, since the etching
solution applied to the substrate underside 21 is not necessarily mixed
directly with said water 27.

[0038] Possibly here the edge areas of the substrate 20 are without a
protective film 29 or, if water 27 does not actually overflow over them
and cover them, they are not protected. At the edges, however, the effect
or damage caused by the etching solution 15 is very small or negligible,
and so said edge areas do not have to be protected.

[0039] Instead of water it is possible to use some other liquid for the
protective film, for example PEG or polyethylene glycol. The latter is
chemically inert and neither reacts with the substrate 20 in an undesired
manner nor impairs the effect of the etching solution 15. It is also
possible to apply phosphoric acid as protective liquid, which does not
adversely impair a substrate such as, for example, a silicon wafer for
solar cells. Its higher viscosity is good primarily for the case where
the substrates have the above-described perforations or pierced holes.

[0040] The exact design of the application nozzles and/or surge pipes, in
particular whether and how many thereof are arranged above the tank 13
with etching solution 15, and also the exact local arrangement thereof,
can be adapted to the respective etching process or treatment step. For
this purpose, by way of example, it is also possible to provide movable
application nozzles and/or surge pipes or use is made in each case of
just a few of a large number structurally provided in principle.

[0041] A top view on an alternative apparatus 111 is illustrated in FIG.
3. Upstream of a tank 113 with edging solution 115 in it four rows of
substrates 120 are running on a continuous passage path composed of
transport rollers similar to the ones of FIG. 1, which are not
illustrated here. There can also be less or more rows, for example six
rows. Upstream of tank 113, a nozzle pipe 125 is running transverse to
the continuous passage path and comprises four application nozzles 126.
These are provided in each case with a magnet valve and nozzle openings,
which are known to a person skilled in the art and need not be
illustrated further. The width of the application nozzles 126 is less
than the width of a substrate 120. The distance of the application
nozzles 126 to each other is the same, but need not be.

[0042] The nozzle pipe 125 is connected to a supply tank 128 in
fluid-conducting manner, in which water 127 for application onto the
substrate top sides 122 is provided. By arranging the supply tank 128 at
a height level above the application nozzles 126, water 127 flows
automatically or on its own accord, respectively, out of it, and by
opening or closing the magnet valves of application nozzles 126 the flow
of water changes or the volume of water stays the same, respectively.
Namely, fluctuations in pressure can be avoided, especially if the magnet
valves of the application nozzles 126 are actuated with an offset to each
other.

[0043] Furthermore, substrate sensors 131 are provided, which are mounted
as an example in this case to the nozzle pipe 125, but can also be
supported separate from it. The substrate sensors 131 detect the arrival,
passing through and passing by of the substrates 120. They can be optical
sensors for example, in particular also as light barrier, which detect
the nearing of a front edge of a substrate 120 as well as the case that a
back edge has passed by. A non-illustrated control device of apparatus
111 receives the signals of the substrate sensors 131 and can then
activate the application nozzles 126 or their valves, respectively, in
such a way that an application of water 127 onto the substrate top sides
122 only takes place if these are positioned beneath them. This ensures
that the water 127 is actually only applied to the substrate top side
122, This is for the purpose that in this case the amount of water can be
limited in a way that the two-dimensionally distributed protective film
129 is formed, but water does not flow over the lateral edges and drools
down. On the one hand, the etching solution 115 in consequence is not
mixed over the tank 113 with or diluted by water. On the other hand, the
etching solution 115 can also act on the lateral edges of the substrate
120 as they are free. Because of the surface tension of the water the
cushion or the layer of water 127, which is also illustrated in FIGS. 1
and 2, can form. Possibly also a substrate 120 with a hydrophilic
substrate top side 122 can be used, which serves for even enhancing this
effect. However, water 127 is applied onto the substrate top sides 122
only once.

[0044] In an alternative embodiment of the invention, which can easily be
figured, the substrate sensors 131 are dispensed with and a control
device of apparatus 111 can calculate from data of a delivery device for
substrates connected upstream when these substrates will be positioned
exactly underneath the application nozzles 126. In this way a precise and
exactly targeted application of water 127 onto the substrate top sides
122 can also take place. Furthermore, significantly more application
nozzles 126 and substrate sensors 131 can be provided neighbouring each
other, which allow the water to be applied onto the substrate top sides
also in the case of differently positioned substrates in an exact way by
means of the application nozzle being most centrally positioned above
them.

Patent applications by Christian Schmid, Freudenstadt DE

Patent applications in class Resist material applied in particulate form or spray

Patent applications in all subclasses Resist material applied in particulate form or spray